integrate test code coverage

[tzemanovic]

this can run in the CI

[james-chf]

cargo llvm-cov works with our codebase, we could use that. It can export the coverage in lcov format which can then be used with IDE plugins like like Coverage Gutters for VS Code, or uploaded to a service like codecov.io.

Proof of concept - https://app.codecov.io/gh/james-chf/namada-fork/tree/james-chf%2Fcoveralls is the coverage for main generated after running the following command (which also requires cargo-nextest ):

cargo llvm-cov nextest \
    --lcov --output-path .hack/lcov.info --features namada/testing -E "not test(e2e)"

[cwgoes]

@james-chf @juped can we integrate automatic coverage?

[james-chf]

I see we already run coverage in CI and publish it as an artifact -

namada/.github/workflows/build-and-test-bridge.yml

Lines 225 to 235 in 076e016

	- uses: taiki-e/install-action@cargo-llvm-cov
	- name: Run unit test
	run: make test-unit-coverage${{ matrix.make.suffix }}
	env:
	RUSTFLAGS: "-C linker=clang -C link-arg=-fuse-ld=/usr/local/bin/mold"
	- name: Upload coverage
	uses: actions/upload-artifact@v3
	with:
	name: coverage${{ matrix.make.suffix }}-${{ github.event.pull_request.head.sha || github.sha }}
	path: target/html
	retention-days: 3

We could probably upload the coverage file as well to a service like https://codecov.io or https://coveralls.io, to get a nice UI for browsing code coverage (there is also some GitHub integrations we could look at e.g. bots that comment on PRs w.r.t. how they increase (or decrease) test coverage)

[grarco]

Closed by #2148